Microcystis aeruginosa is a common species of
cyanobacteria (often called blue-green algae) that blooms in the fresh and low salinity
portions of the Chesapeake and Coastal Bays and can become quite striking if it floats and
forms a surface scum. The water may show the appearance of blue-green paint floating or
billowing near the surface. Ingestion of waters containing high concentrations of Microcystis
can cause abdominal stress in humans leading to precautionary beach closures and
can kill dogs and farm animals if they drink significant quantities of